From a72b71498cdb2e459f6b0217e36f54405c8da4d2 Mon Sep 17 00:00:00 2001
From: Pier Angelo Vendrame <pierov@torproject.org>
Date: Tue, 26 Mar 2024 17:39:01 +0100
Subject: [PATCH] Bug 41901: Hardcode normalized FontSubstitutes.
Windows has a system to set font aliases through the registry.
This allows some customization that could be used as a fingerprinting
vector.
Moreover, this mechanism is used by Windows itself, and different SKUs
might have different default FontSubstitutes.
---
gfx/thebes/StandardFonts-win10.inc | 65 +++++++++++++++++++++++++
gfx/thebes/gfxDWriteFontList.cpp | 77 +++++++++++++++++++-----------
gfx/thebes/gfxDWriteFontList.h | 3 ++
gfx/thebes/gfxGDIFontList.cpp | 28 +++++++++++
4 files changed, 145 insertions(+), 28 deletions(-)
diff --git a/gfx/thebes/StandardFonts-win10.inc b/gfx/thebes/StandardFonts-win10.inc
index c929992ed865f..81cf30cc376f3 100644
--- a/gfx/thebes/StandardFonts-win10.inc
+++ b/gfx/thebes/StandardFonts-win10.inc
@@ -200,3 +200,68 @@ static const char* kLangPackFonts[] = {
// "Rockwell Nova", // Pan-European Supplemental Fonts - EXCLUDED
// "Verdana Pro", // Pan-European Supplemental Fonts - EXCLUDED
};
+
+struct FontSubstitute {
+ const char *substituteName;
+ const char *actualFontName;
+};
+
+static const FontSubstitute kFontSubstitutes[] = {
+ // Common substitutions
+ {"Arabic Transparent", "Arial"},
+ {"Arabic Transparent Bold", "Arial Bold"},
+ {"Arial Baltic", "Arial"},
+ {"Arial CE", "Arial"},
+ {"Arial CYR", "Arial"},
+ {"Arial Greek", "Arial"},
+ {"Arial TUR", "Arial"},
+ {"Courier New Baltic", "Courier New"},
+ {"Courier New CE", "Courier New"},
+ {"Courier New CYR", "Courier New"},
+ {"Courier New Greek", "Courier New"},
+ {"Courier New TUR", "Courier New"},
+ {"Helv", "MS Sans Serif"},
+ {"Helvetica", "Arial"},
+ {"MS Shell Dlg 2", "Tahoma"},
+ {"Tahoma Armenian", "Tahoma"},
+ {"Times", "Times New Roman"},
+ {"Times New Roman Baltic", "Times New Roman"},
+ {"Times New Roman CE", "Times New Roman"},
+ {"Times New Roman CYR", "Times New Roman"},
+ {"Times New Roman Greek", "Times New Roman"},
+ {"Times New Roman TUR", "Times New Roman"},
+ {"Tms Rmn", "MS Serif"},
+ // Common, except Japanese (which uses MS UI Gothic, instead)
+ {"MS Shell Dlg", "Microsoft Sans Serif"},
+ // Arabic
+ {"Arial (Arabic)", "Arial"},
+ {"Courier New (Arabic)", "Courier New"},
+ {"Times New Roman (Arabic)", "Times New Roman"},
+ // Cyrillic + Greek
+ {"Courier", "Courier New"},
+ // Greek
+ {"Fixedsys Greek", "Fixedsys"},
+ {"MS Serif Greek", "MS Serif"},
+ {"MS Sans Serif Greek", "MS Sans Serif"},
+ {"Small Fonts Greek", "Small Fonts"},
+ {"System Greek", "System"},
+ // Hebrew
+ {"Arial (Hebrew)", "Arial"},
+ {"Courier New (Hebrew)", "Courier New"},
+ {"David Transparent", "David"},
+ {"Fixed Miriam Transparent", "Miriam Fixed"},
+ {"Miriam Transparent", "Miriam"},
+ {"Rod Transparent", "Rod"},
+ {"Times New Roman (Hebrew)", "Times New Roman"},
+ // Japanese
+ {"標準明æœ", "ï¼ï¼³ 明æœ"},
+ {"標準ゴシック", "ï¼ï¼³ ゴシック"},
+ {"ゴシック", "ï¼ï¼³ ゴシック"},
+ {"ｺﾞｼｯｸ", "ï¼ï¼³ ゴシック"},
+ {"ｸｰﾘｴ", "Courier"},
+ {"ﾀｲﾑｽﾞﾛï¾ï¾", "Times New Roman"},
+ {"ï¾ï¾™ï¾ï¾žï¾ï½¶", "Arial"},
+ // Simplified Chinese
+ {"FangSong_GB2312", "FangSong"},
+ {"KaiTi_GB2312", "KaiTi"},
+};
diff --git a/gfx/thebes/gfxDWriteFontList.cpp b/gfx/thebes/gfxDWriteFontList.cpp
index 8595004d21002..f06fba22133f6 100644
--- a/gfx/thebes/gfxDWriteFontList.cpp
+++ b/gfx/thebes/gfxDWriteFontList.cpp
@@ -1953,6 +1953,20 @@ static void RemoveCharsetFromFontSubstitute(nsACString& aName) {
#define MAX_VALUE_DATA 512
nsresult gfxDWriteFontList::GetFontSubstitutes() {
+ if (nsContentUtils::ShouldResistFingerprinting(
+ "Ignore any fingerprintable user font customization and normalize "
+ "font substitutes across different Windows SKUs.",
+ RFPTarget::FontVisibilityLangPack)) {
+ for (const FontSubstitute& fs : kFontSubstitutes) {
+ nsAutoCString substituteName(fs.substituteName);
+ nsAutoCString actualFontName(fs.actualFontName);
+ BuildKeyNameFromFontName(substituteName);
+ BuildKeyNameFromFontName(actualFontName);
+ AddSubstitute(substituteName, actualFontName);
+ }
+ return NS_OK;
+ }
+
HKEY hKey;
DWORD i, rv, lenAlias, lenActual, valueType;
WCHAR aliasName[MAX_VALUE_NAME];
@@ -1987,39 +2001,46 @@ nsresult gfxDWriteFontList::GetFontSubstitutes() {
BuildKeyNameFromFontName(substituteName);
RemoveCharsetFromFontSubstitute(actualFontName);
BuildKeyNameFromFontName(actualFontName);
- if (SharedFontList()) {
- // Skip substitution if the original font is available, unless the option
- // to apply substitutions unconditionally is enabled.
- if (!StaticPrefs::gfx_windows_font_substitutes_always_AtStartup()) {
- // Font substitutions are recorded for the canonical family names; we
- // don't need FindFamily to consider localized aliases when searching.
- if (SharedFontList()->FindFamily(substituteName,
- /*aPrimaryNameOnly*/ true)) {
- continue;
- }
- }
- if (SharedFontList()->FindFamily(actualFontName,
+ AddSubstitute(substituteName, actualFontName);
+ }
+
+ return NS_OK;
+}
+
+void gfxDWriteFontList::AddSubstitute(const nsCString& substituteName,
+ const nsCString& actualFontName) {
+ if (SharedFontList()) {
+ // Skip substitution if the original font is available, unless the
+ // option to apply substitutions unconditionally is enabled.
+ if (!StaticPrefs::gfx_windows_font_substitutes_always_AtStartup()) {
+ // Font substitutions are recorded for the canonical family names;
+ // we don't need FindFamily to consider localized aliases when
+ // searching.
+ if (SharedFontList()->FindFamily(substituteName,
/*aPrimaryNameOnly*/ true)) {
- mSubstitutions.InsertOrUpdate(substituteName,
- MakeUnique<nsCString>(actualFontName));
- } else if (mSubstitutions.Get(actualFontName)) {
- mSubstitutions.InsertOrUpdate(
- substituteName,
- MakeUnique<nsCString>(*mSubstitutions.Get(actualFontName)));
- } else {
- mNonExistingFonts.AppendElement(substituteName);
+ return;
}
+ }
+ if (SharedFontList()->FindFamily(actualFontName,
+ /*aPrimaryNameOnly*/ true)) {
+ mSubstitutions.InsertOrUpdate(substituteName,
+ MakeUnique<nsCString>(actualFontName));
+ } else if (mSubstitutions.Get(actualFontName)) {
+ mSubstitutions.InsertOrUpdate(
+ substituteName,
+ MakeUnique<nsCString>(*mSubstitutions.Get(actualFontName)));
} else {
- gfxFontFamily* ff;
- if (!actualFontName.IsEmpty() &&
- (ff = mFontFamilies.GetWeak(actualFontName))) {
- mFontSubstitutes.InsertOrUpdate(substituteName, RefPtr{ff});
- } else {
- mNonExistingFonts.AppendElement(substituteName);
- }
+ mNonExistingFonts.AppendElement(substituteName);
+ }
+ } else {
+ gfxFontFamily* ff;
+ if (!actualFontName.IsEmpty() &&
+ (ff = mFontFamilies.GetWeak(actualFontName))) {
+ mFontSubstitutes.InsertOrUpdate(substituteName, RefPtr{ff});
+ } else {
+ mNonExistingFonts.AppendElement(substituteName);
}
}
- return NS_OK;
}
struct FontSubstitution {
diff --git a/gfx/thebes/gfxDWriteFontList.h b/gfx/thebes/gfxDWriteFontList.h
index 357336a12cc05..d416c0a8d5349 100644
--- a/gfx/thebes/gfxDWriteFontList.h
+++ b/gfx/thebes/gfxDWriteFontList.h
@@ -457,6 +457,9 @@ class gfxDWriteFontList final : public gfxPlatformFontList {
const nsTArray<nsCString>* aForceClassicFams = nullptr)
MOZ_REQUIRES(mLock);
+ void AddSubstitute(const nsCString& substituteName,
+ const nsCString& actualFontName);
+
#ifdef MOZ_BUNDLED_FONTS
already_AddRefed<IDWriteFontCollection> CreateBundledFontsCollection(
IDWriteFactory* aFactory);
diff --git a/gfx/thebes/gfxGDIFontList.cpp b/gfx/thebes/gfxGDIFontList.cpp
index 4dca4506c0ac6..a3257d540d839 100644
--- a/gfx/thebes/gfxGDIFontList.cpp
+++ b/gfx/thebes/gfxGDIFontList.cpp
@@ -31,6 +31,10 @@
#include "mozilla/StaticPrefs_gfx.h"
#include "mozilla/Telemetry.h"
+#include "nsContentUtils.h"
+
+#include "StandardFonts-win10.inc"
+
#include <usp10.h>
using namespace mozilla;
@@ -50,6 +54,10 @@ static __inline void BuildKeyNameFromFontName(nsAString& aName) {
if (aName.Length() >= LF_FACESIZE) aName.Truncate(LF_FACESIZE - 1);
ToLowerCase(aName);
}
+static __inline void BuildKeyNameFromFontName(nsACString& aName) {
+ if (aName.Length() >= LF_FACESIZE) aName.Truncate(LF_FACESIZE - 1);
+ ToLowerCase(aName);
+}
// Implementation of gfxPlatformFontList for Win32 GDI,
// using GDI font enumeration APIs to get the list of fonts
@@ -529,6 +537,26 @@ static void RemoveCharsetFromFontSubstitute(nsAString& aName) {
#define MAX_VALUE_DATA 512
nsresult gfxGDIFontList::GetFontSubstitutes() {
+ if (nsContentUtils::ShouldResistFingerprinting(
+ "Ignore any fingerprintable user font customization and normalize "
+ "font substitutes across different Windows SKUs.",
+ RFPTarget::FontVisibilityLangPack)) {
+ for (const FontSubstitute& fs : kFontSubstitutes) {
+ nsAutoCString substituteName(fs.substituteName);
+ nsAutoCString actualFontName(fs.actualFontName);
+ BuildKeyNameFromFontName(substituteName);
+ BuildKeyNameFromFontName(actualFontName);
+ gfxFontFamily* ff;
+ if (!actualFontName.IsEmpty() &&
+ (ff = mFontFamilies.GetWeak(actualFontName))) {
+ mFontSubstitutes.InsertOrUpdate(substituteName, RefPtr{ff});
+ } else {
+ mNonExistingFonts.AppendElement(substituteName);
+ }
+ }
+ return NS_OK;
+ }
+
HKEY hKey;
DWORD i, rv, lenAlias, lenActual, valueType;
WCHAR aliasName[MAX_VALUE_NAME];
--
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